Disazo dyes from dihydroxy benzidines



Patented Sept. 9, 1947 DISAZO DYES FROM DIHYDROXY BENZIDINES Fritz Straub, Kaiseraugst, and Jakob Brassel and Peter Pieth, Basel, Switzerland, assignors to Society of Chemical Industry in Basle, Basel, Switzerland, a Swiss firm No Drawing. Application August 16, 1943, Serial No. 498,884. In Switzerland February 18, 1941 6 Claims.

This application is a continuation-in-part of our copending application Serial No. 431,172, filed February 16, 1942.

The present invention is concerned with valuable new disazo dyestuffs, and a process for preparing the same. The present invention is particularly concerned with direct dyeing cotton dyestuffs (also called substantive dyestuffs), and still more particularly with dyestuffs capable of being metallized, for instance coppered, in substance, in the dye-bath or on the fiber, as the case may be.

According to the present invention tetrazotized 3 3-dihydroXy-4 4' -diaminodiphenyl is coupled with two molecular proportions of coupling components as defined hereinafter.

3:3-dihydroxy-4:4-diaminodiphenyl, which is a known compound and which may be obtained for instance by saponifying dianisidine by means of aluminum chloride, has not hitherto found any industrial use. Although a few 'dyestuifs prepared with tetrazotized 3:3 dihydroxybenzidine have been described in the literature, the said compound has generally been regarded to be of no practical value. This is probably due to several facts. First of all it was generally believed that the said product would be too eX- ensive for the commercial manufacture of dyestuffs. Furthermore, the very few dyestuffs hitherto prepared with the said tetrazo compound did not show properties which might make them compete successfully with other dyestuffs, and it is to be remarked that, according to the prescriptions found in the literature, correct coupling is in most cases not brought about, which obviously does not lead to correct disazo dyestuffs.

According to the present invention it has been found that the cost of 3:3'-dihydroxy-4:4'- diaminodiphenyl is by no mean prohibitive for the manufacture of dyestuffs therefrom, since such dyestuffs as hereinafter definedshow very valuable properties which more than outweigh any difiiculties encountered in preparing the said starting material. Further, it will be shown hereinafter that correct coupling to form correct disazo dyestufis can be brought about, and that dyestuffs of much superior properties can be produced thereby.

For the sake of simplicity coupling may be carried out with two molecular proportions of the same couplin component. However, it is not unduly difiicult to effect coupling with two different coupling components since tetrazotized 3:3'-dihydroxy-4:4-diaminodiphenyl has a great tendency to couple first with one diazo group and afterwards with the other.

3 3'-dihydroXy-4 4' -diaminodiphenyl may be obtained by saponification of dianisidine by means of aluminum chloride and may be purified if necessary according to known methods. It may be tetrazotized in known manner and the tetrazo compound-may be used immediately after tetrazotizing or may be separated, as described in the examples below.

According to one feature of the present invention tetrazotized 3 3-dihydroXy-4 l -diaminodiphenyl is coupled with two molecular proportions of coupling components, at least one of which contains at least one nitrogen atom having attached thereto at most one hydrogen atom.

The coupling components containing nitrogen mentioned above, may belong to the isocyclic, heterocyclic or open chain series. As a first group of such component hydroxy naphthalenes containing at least one nuclearly bound sulfonic acid group are to be mentioned. They must contain at least one nitrogen atom which is bound in a form different from primary amino groups. Thus it may be in the form of secondary or acylated amino group, e. g., as an imide linkage between two radicals such as in 5:5'-dihydroxy-2 2 -dinaphthylamino-7 '7 -disulfonic acid, 2-phenylamino-5-hydroxynaphthalene-7-sulionic acid, Z-phenylamino 8 hydroxynaphthalene-fisulfonic acid, or in form of an acid amide group such as in l-toluenesulfonylamino-8-hydroxynaphthalene i-sulfonic acid or in the form of a nitro group. The said nitrogen atom may further be present as a member of a heterocyclic ring such a in pyrazolones. It is, as a rule, desirable to select the coupling components so as coupling will take place in the ortho position to a hydroxyl group.

Besides the above mentioned coupling components other suitable components, such as aminonaphtholsulfonic acids in which the amino group is acylated by any suitable carboxylic or sulfonic acid, may be used, wherein the acid may be aliphatic (formic, acetic, propionic acid etc.) aromatic (benzoic, naphthoic acid etc.) or heterocyclic (pyridine-carbamic acid etc.) and contain further substituents. If only one coupling component of this kind is used as remaining coupling components any such component may be used, for instance those belonging to the benzene, naphthalene or open-chain series.

Such components are, for example, the various dihydroxynaphthalenes, such as -1:5-, 2:6- and -2:7-dihydroxy-naphthalene, Z-amino 7 hydroxynaphthalene, l-amino-T-hydroxynaphthalene, 2:6 dihydroXynaphthalene-monoglycerine ether, as well as N-substituted amino-hydroxynaphthalenes, in which the amino group, for example, can be substituted by alkyl or hydroxyalkyl radicals. Furthermore such hydroxynaphthalenes also come into consideration which contain other substituents besides those mentioned above, e. g. a sulfonamide group.

Particularly valuable dyestufis are obtained if hydroxynaphthalenes are used which are absolutely free from water solubilizing groups and, for example, are also free from carboxyl groups. These dyestuffs can be advantageously dyed from baths rendered alkaline with alkali hydroxide.

According to another feature of the present invention a tetrazotized 3:3-dihydroxy-4:4-diamino diphenyl is coupled with two molecular proportions of coupling components at least one of which is a l-hydroxynaphthalene containing an auxochroinic group in the 8-position. Such auxochromic groups are, for instance, an amino or a substituted amino group, or a further hydroxyl group. or any other group possessing auxochrome properties. These coupling components may carry further substituents in suitable positions of the naphthalene nucleus, for instance solubilizin'g groups, such as sulfonic acid or carboxyl groups or both, as well as non-solubilizing substituents, such as halogen.

In all the instances mentioned above coupling is effected in an alkaline medium. It is to be remarked, however, that there are many coupling components, especially those of the naphthalene series, which do not combine in a satisfactory manner with tetrazotized 3:3'-dihydroxy-4.:4- diaminodiphenyl when coupling occurs in the usual manner, i. e. in a medium alkaline with sodium carbonate, even if pyridine or similar promoters are added. Th combination is often incomplete to such an extent that only little or no diazo dyestufi is produced, and a monoazo dyestuff is obtained as main product. It is a further feature of the present invention that in all instances where combination is slow and/or incomplete with the usual coupling methods, coupling is eifected in a medium alkaline with a hydroxide of the alkali or alkaline earth metal series including ammonia. It is often desirable to use strongly caustic alkaline media, for instance strong solutions of caustic potash or soda, but, in other instances, the hydroxides of calcium, barium, strontium or magnesium are suitable too, whereas media substantially free from carbonate generally appear to be desirable whenever combination is difiicult.

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The disazo dyestufis of the present invention are suitable for dyeing and printing the most diverse materials, especially cellulose fibers, such as cotton and other vegetable fibers, rayon from regenerated cellulose including staple fibers, and also for dyeing and printing animal fibers such as wool, silk and leather. Due to the fact that the said dyestulfs are derived from an ortho-hydroxydiazo compound they are capable of forming complex metal compounds, for instance, with the metals copper, cobalt, nickel, iron, chromium, vanadium, manganese.

Many of the foregoing dyestuffs yield very valuable complex metal compounds if treated in substance with agents yielding metal. This is especially true of those dyestuffs which contain more than two sulfonic acid groups, for instance those derived from two coupling components belonging to the group of hydroxynaphthalene disulfonic acid coupling components. With other dyestuffs it may be more advantageous to efiect metallization during or, still better, after dyeing according to the known aftertreating methods. With special advantage use may be made of the dyeing methods described in U. S. Patents 2,148,- 659 and 2,185,905, whereby metallizing is preferably carried out with agents yielding metal which are stable towards alkalies, for instance complex tartrates of copper or other metals.

In some cases it may also be useful to treat some dyestuffs as mentioned above in substance with such alkaline metallizing agents.

Furthermore it is possible to make use of complex metal compounds of the dyestuifs according to the present invention for coloring masses, varnishes, lacquers, resins, both artificial and natural, and spinning solutions.

Whether it is preferable to produce the aforementioned complex metal compounds on the fiber or in substance depends on various properties thereof, inter alia, whether the complex metal compounds are soluble, whether the metal-free dyestuffs possess suificient amnity for the fiber to be dyed, etc.

The following examples illustrate the invention, the parts being by weight unless otherwise stated:

Example 1 10.8 parts of 3:3-dihydroxybenzidine are tetrazotized in the usual manner in a hydrochloric acid solution with sodium nitrite. The crystalline precipitated tetrazoxide is added to a mixture of 37.5 parts 2- (4-hydroxy-3'-carboxyphenyl) -amino-5-hydroXynaphthalene-7-sulfonic acid and 36 parts calcium hydroxide in 200 parts of water cooled to 5 C. Stirring is carried out for 2 hours at 5 to 8 0., for 24 hours at 15 to 20 C. and coupling is finished at 28 to 30 C. The coupling mixture is diluted with 1000 parts Of hot water and 60 parts of anhydrous sodium carbonate are added. After stirring for half an hour at 50 0., the liquid is filtered off from the precipitated calcium carbonate. After neutralizing with hydrochloric acid, the dyestufi is precipitated from the filtrate by the addition of sodium The dyestuff of the formula coon is a dark powder and dyes cotton. After coppering it yields pure blue shades which are fast to washing and light.

Example 2 21.6 parts of 3:3'-dihydroxy-4:4-diaminodiphenyl in the form of the hydrochloride, are stirred in parts of Water and 12 parts of concentrated hydrochloric acid and tetrazotized at 5 to 8 C. with an aqueous solution of 13.8 parts of sodium nitrite. When the reaction is complete the suspension is cooled to 3 C. and neutralized by the addition of 6.4. parts anhydrous 2,426,977 d 5 6 so ium carbonate and the precipitated tetrazo v mpound is filtered off. ple 4.

58.5 parts of Z-(c-hydroxyethyl)-amino-5- 21.6 parts of 3;3'-dihydro 4: r

hydroxy-naphthalene-7-sulfonic acid are stirred phenyl a tetrazotized, neut a a d filt red into a freshly prepared milk of lime consisting 5 as describedin Examp of 22.4 parts of burnt lime and 280 parts of water. 64.5 parts f -p y y p hi is cooled t d th above mentioned thalene-4sulfonic' acid are dissolved in 160 parts tetrazo compound is added and coupling is carby Volume of caustic potash 0f 0 p 13 ried out during 4 hours at 5 to 8 C. during 24 Strength by V l e and a e o ed to C. The

hours at 10-15 C. and until th r ti i 10 filtered tetrazo solution is added, and the whole plete at 20 to 30 C. I-Iereupon it is diluted with is stirred for 2 hours at 5-8 C. and t 11111311 2000 parts of water at 50 C. and 60 parts of soda coupling is p t at C- T new d Sa O are added and the liquid filtered from the predyestuff is for the most part p ipitated. It is cipitated calcium carbonate. 120 parts of sodium filtered ff a d purified by dissolving in dilute chloride are added to the filtrate and the new soda solution and salting out.

dyestufi is precipitated by adding drop by drop T e new dy f 0 t e mu a 200 parts of hydrochloric acid of 10 percent strength. NE on no NH- When dried the resultant powder is black with NAT a bronzyappearance. The new dyestuff yields i iO pure blue shades which have very good fastness H 6 properties on being dyed and coppered on cotton by either a one or two bath process. 803E 803E is a black powder when dry which dissolves in Egzample 3 water with a blue color, in 10 per cent. soda solu- 21.6 parts of 3:3'-dihydroxy-4:4'-diaininodition to a greenish-blue, in 10 per cent. caustic phenyl, in the form of its dichlorhydrate, are soda to a reddish blue and in concentrated sulstirred in 100 parts of water and 12 parts of confuric d a bluish r n s ut When y centrated hydrochloric acid and is tetrazotized d C Dp y a One 0 a 11 l a methodby addition of an aqueous solution of 13.8 parts n ott it y r ne s a s of o of sodium nitrite at 5-8 0. When tetrazotizaast ess.

tion is complete, the suspension is cooled to 3 C.,

neutralized by addition of 6.4 parts of soda and Exammle 5 filtered to obtain the precipitated tetrazo com- 216 Parts Of Y Y- IF-d a mdipound. phenyl are tetrazotized, neutralized and filtered 103 parts of the disodium salt of 5:5-dihyas described in Example droxy-2:2'-dinaphthylamine-'7:7'-disu1fonic acid 81 pa ts of 1t0 u -su y1amin 8hyare dissolved in 130 parts of water and 30 part droxynaphthalene-4-sulfonic acid are stirred in of potassium hydroxide. The solution is cooled 240 parts of water and 29.6 parts of slaked lime to 5 C and the above tetrazo compound i dd d 40 are added. The reaction mixture is cooled to 5 to it whilst stirring thoroughly. Coupling is r- C. and the filtered tetrazo solution is added.

ried out for 2 hours at 543 c. and 24 hours at C up n s a d out for 2 h u s at 58 C-, l015 C. Finally, the coupling temperatu i then for 24 hours at 10-15 0., and, to conclude raised to 20-30" C. When coupling is complete, the reaction, for 24 hours at 20-25 C. The rethe mass is diluted with 1000 parts of Water, 65 action ss is h n diluted w 800 parts f p rts of sodium chloride are added at C. and water. A solution of 6 parts of Soda n 300 the dyestufi' is precipitated by addition of 200 Parts Of Water is added, a d e Solution is filparts by volume of hydrochloric acid of 5 per cent, tered from the calcium carbonate precipitated.

strength. The disazo dyestufi is purified by dis- The new dy stu f s pa t y sa t d ut y dditi n solving it in 2000 parts of water and 10.6 parts of 50 of 150 parts of common salt, and salting out is soda, and salting it ut, completed by dropping in 140 parts of 10 per It possesses the formula cent hy c ac dand, when dried, is a black, bronzy powder which dissolves in water to a, violet solution, in 10 per The new dyestuff possesses the formula CH3 -SO2-NH on no NH-SOP CH3 6H (in SOsH 1 soiH i cent. soda solution to a blue solution, in 10 per 7 and, when dry, is a bronzy black powder, discent. caustic soda solution to a blue-violet and solving in water to a blue, in 10 per cent. caustic in concentrated sulfuric acid to a greenish-blue soda to a reddish blue, in 10 per cent. soda solusolution. The new disazo dyestufi yields fast blue tion to a blue and in concentrated sulfuric acid shades on being dyed and coppered on cotton by to a green solution. When dyed on cotton and either a one or two bath process. aftertreated with copper salts, either by a oneor by a two-bath process, green shades of good fastness are obtained.

Example 6 is, in the dry state, a dark colored powder, which dissolves in water to a violet and in sulfuric acid and dilute alkalis to a bluev solution. It dyes cotton and regenerated cellulose in blue shades which, especially when treated with copper salts, possess excellent fastness to washing and light.

Example 7 21.6 parts of 3:3-dihydroXy-4:4-diaminodiphenyl are tetrazotized, neutralized and filtered as described in Example 3.

103 parts of the disodium salt of 5:5-dihydroxy 2:2. dinaphthylamine 7:7 disulfonic acid are dissolved in 190 parts of water and 30 parts of caustic soda. The solution is cooled to 5 C., and the filtered tetrazo solution is introduced whilst stirring well. The coupling temperature is maintained for 2 hours at 58 C., 24 hours at Lil- C. and, finally, several hours at 25 C. When the coupling is complete, the mass is diluted with 1000 parts of water at 55 C., 60 parts of common salt are added and the dyestufi is precipitated by addition of 200 parts by volume of 5 per cent. hydrochloric acid. The new disazo dyestufi can be purified by dissolving it in dilute soda solution and salting out.

When dry, it is a bronzy black powder which dissolves in water to a violet, in 10 per cent. soda solution to a blue, in 10 per cent. caustic soda to a blue violet, and in concentrated sulfuric acid to a green-blue solution. When dyed on cotton and coppered, by either a oneor a two-bath process, it yields fast blue shades.

Example 8 21.6 parts of 3:3'-dihydroxy-4:4-diaminodiphenyl are tetrazotized as described in Example 3, the solution is neutralized with soda solution and the precipitated tetra'zo compound is filtered off.

103 parts of the disodium salt of 5:5-dihydroxy 2:2 dinaphthylamine 7:7 disulfonic acid are dissolved in 300 parts of water and 100 The new dyestufl, when dry, is a black powder which dissolves in water to a violet, in 10 per cent. soda solution to a blue, in 10 per cent. caustic soda to a blue violet, and in concentrated sulfuric acid to a greenish blue solution. When dyed on cotton and aftertreated with copper salts, either by a one-bath or by a two-bath process, it yields blue shades having very good fastness properties.

Example 9 10.8 parts of 3:3-dihydroxybenzidine are tetrazotized in the usual manner with 6.9 parts of sodium nitrite in the presence of hydrochloric acid. The crystallized tetrazoxide is filtered off and at 5 C. is added to a mixture of 12 parts of 1:8-dihydroxynaphthalene-4-sulfonic acid and 20 parts calcium hydroxide in 150 parts of Water. Stirring is carried out for 1 hour at 5 to 8 C. and for 1 hour at 10 to 15 C. Hereupon a mixture of 15.8 parts of 2phenylamino-5-hydroxynaphthalene-l-gulfonic acid, 9 parts calcium hydroxide and 100 parts of water is added and stirred for 1 hour at 15 to 20 C. and coupling is carried to an end at 25 to 30 C. The couplin mixture is diluted with 1000 parts of hot water and after the addition of 65 parts of anhydrou sodium carbonate, the temperature is maintained at to C. for half an hour. The liquid is filtered off from the precipitated calcium carbonate and sodium chloride and hydrochloric acid are added to the filtrate. The disazo dyestufi is filtered off and dried; When dry it forms a dark green bronzy powder which dissolves in Water and dilute caustic alkalies to reddish blue, in dilute soda solution to a cornflower blue and in concentrated sulfuric acid to a greenish blue solution. It yields pure blue shades of very good fastness to Washing and light on being dyed and coppered on vegetable fibers by either a one or two bath process.

If in the present example IiS-dihydroxynaphthalenebsulfonic acid is replaced by an equivalent quantity of 2-(4-hydroxy 3 carboxyphenyl) -an1ino-5-hydronaphtha1ene '7 sulfonic acid, then a dyestufi is obtained which produces almost the same shades of similar fastness properties.

' Example 10 21.6 parts of 3:3'-dihydroxy-i:4'-diaminodiphenyl are dissolved in a mixture of 10 parts by volume of hydrochloric acid of 30% strength and 200 parts of waterand are tetrazotizedby addi-' tion of an aqueous solution of 13.8 parts of sodium nitrite; the reaction mixture is then neutralized and the tetra-Z0 compound filtered off.

75 parts of 1-acetylamino-8-hydroxynaphthalene-3z6-disulfonic acid are stirred into a suspension of 30 parts of calcium hydroxide in 300 parts of water and cooled to 3 C. The filtered tetrazo compound is added and coupling carried out for 3 hours at 3 to 5 C., for 2 hours at 5 to 10 C., for 16 hours at 10 to 15 C.'and till the termination of the reaction at 20 to 25 C. Hereupon it is diluted with 400 parts of'water and a solution of 45 parts of soda in 250 parts of water is added and the liquid filtered off from the calcium carbonate. The new dyestufi is precipitated by the addition of sodium chloride.

When y it forms a black p er which yields It is to be understood that the term hydroxide blue shades with good fa s properties on being of the alkali metal series includes aqueous soludyed and coppered on cotton by either a one or tions of ammonia.

two bath process. What We claim is:

Example 11 1. Disazo dyestuffs of the general formula 105 parts of the disazo dyestufi obtained according to Example from tetrazotized 3 :3'-dihydroXy-4:4'-diaminodiphenyl and 2 molecular pro- H 5;;

portions of 1-acetylamino-8-hydroxynaphtha- 1o lene-3:6-disulfonic acid are dissolved in 3000 parts of Water at 80 C. and stirred for 15 minutes with a solution of 55 parts of copper sulphate made alkaline with soda and 110 parts of sodium tartrate. The new copper compound is obtained wherein R1 and R2 stand for radicals of aminohydroxy-naphthalene sulfonic acids wherein the amino group is selected from the group consisting of acylated, alkylated and arylated secondary amino groups.

15 2. Disazo dyestufis of the general formula by salting out.

When dry it forms a greyish black powder which dyes cotton pure blue shades with good N N NN fastness properties. 5 I

Emample 12 wherein R1 and R2 stand for radicals selected 21.6 parts of 3:3'-dihydroxy-e:l-diaminodifrom the group consisting of arylamino-hydroxyphenyl are tetraoztized as described in Example naphthalene sulfonic acids of the benzene and 3, the solution is neutralized with soda solution naphthalene series. and the precipitated tetrazo compound is filtered 3. Disazo dyestufis of the general formula oil.

66 parts of 1-amino-8-hydroxynaphthalene- R1N=N OON=N R2 3:6-disulfonic acid are stirred in 200 parts of wa (g ter and 29.6 parts of calcium hydroxide are E H added. The suspension is cooled to 5 C., and the wherein R1 and R2 stand for radicals of phenylfiltered tetrazo compound is added. The coupling amino-hydroxynaphthalene sulfonic acids. temperature is maintained for 2 hours at 58 C. 4. The disazo dyestuff of the formula and then for 24 hours at 10-20 0., when a solu- 5. The disazo dyestuff of the formula HO NH SO3H HOaS -NHQOH d 0 OH N=NQQN=N 0 OH H H H OH tion of 60 parts of soda in 300' parts of water at 6. The disazo dyestuff of the formula H033 -NH -SO3H H038 NH -sosn N=N-Q N=N OH H H H OH H C. is added to the reaction mass, and the cal- FRITZ STRAU'B. cium carbonate is removed by filtering. The fil- JAKOB BRASSEL. trate is stirred with 100 parts of common salt, PETER PIETH. and the new dyestuff is obtained by dropping in 135 parts of 10 per cent hydrochloric acid. R FERENCES CITED 96.4 parts of the disazo dyestufi thus obtained The following references are of record in the are dissolved in 3500 parts of water at C. 40 fil of this patent: parts of acetic anhydride are added and the whole stirred for 10 minutes. The acetyl com- UNITED STATES PATENTS pound of the disazo dyestuff is precipitated by the Number Name Date addition of sodium chloride. The acetyl compound of the disazo dyestuff is dissolved in 2000 (w i i 3 2 parts of water at C. and a solution of 55 parts 2241796 n erWer e a e of crystallized copper sulphate made alkaline with 93,43 Taube et a] May 1941 soda and parts of sodium tartrate in 500 parts )1 a 8 Taube a1 1940 g; zvagzgr cagre added and stirred for 15 minutes at 70 FOREIGN PATENTS 0 The new copper compound is precipitated by Number Country Date adding sodium chloride. 10 ,381 Great Britain Jan. 4, 1917 When dry it forms a greyish black powder 16,092 Great Britain July 22, 1909 which yields on cotton pure blue shades with good 352,956 Great Britain July 14, 1931 fastness properties. 75 163,896 Switzerland Nov. 16, 1933 

